The end of the year tends to be a time when many of us increase our charitable giving. Before you send your donations, though, consider this: If you're dividing your gifts among more than a couple of organizations, your money isn't going as far towards the cause as it could.

CNN Money notes that every donation has a fixed cost for the charity to steward it. The smaller the donation, the greater the percentage that goes to transaction costs—and the less towards your actual cause. So instead of diving your money among many charities, it's better to give that money to one or two of them.

If you don't want to limit your donations to just two causes, though, CNN Money recommends a "50/20/30 rule":

Half your giving should be focused on one charity — the gift you'll spend the most time thinking about. Then set aside 20% for small impulse gifts and the final 30% for institutions you support on a regular basis, like your alma mater or your church.

Check out the full article for more donation strategies and tips, including not giving to charities when they call you (telemarketing firms can take more than half of what you donate for themselves). That's probably something we're all happy to never do again.